Elevational Gradients in Bird Diversity in the Eastern Himalaya: An Evaluation of Distribution Patterns and Their Underlying Mechanisms

BACKGROUND: Understanding diversity patterns and the mechanisms underlying those patterns along elevational gradients is critically important for conservation efforts in montane ecosystems, especially those that are biodiversity hotspots. Despite recent advances, consensus on the underlying causes, or even the relative influence of a suite of factors on elevational diversity patterns has remained elusive. METHODS AND PRINCIPAL FINDINGS: We examined patterns of species richness, density and range size distribution of birds, and the suite of biotic and abiotic factors (primary productivity, habitat variables, climatic factors and geometric constraints) that governs diversity along a 4500-m elevational gradient in the Eastern Himalayan region, a biodiversity hotspot within the world's tallest mountains. We used point count methods for sampling birds and quadrats for estimating vegetation at 22 sites along the elevational gradient. We found that species richness increased to approximately 2000 m, then declined. We found no evidence that geometric constraints influenced this pattern, whereas actual evapotranspiration (a surrogate for primary productivity) and various habitat variables (plant species richness, shrub density and basal area of trees) accounted for most of the variation in bird species richness. We also observed that ranges of most bird species were narrow along the elevation gradient. We find little evidence to support Rapoport's rule for the birds of Sikkim region of the Himalaya. CONCLUSIONS AND SIGNIFICANCE: This study in the Eastern Himalaya indicates that species richness of birds is highest at intermediate elevations along one of the most extensive elevational gradients ever examined. Additionally, primary productivity and factors associated with habitat accounted for most of the variation in avian species richness. The diversity peak at intermediate elevations and the narrow elevational ranges of most species suggest important conservation implications: not only should mid-elevation areas be conserved, but the entire gradient requires equal conservation attention

Modelling mammalian energetics: the heterothermy problem

Global climate change is expected to have strong effects on the world’s flora and fauna. As a result, there has been a recent increase in the number of meta-analyses and mechanistic models that attempt to predict potential responses of mammals to changing climates. Many models that seek to explain the effects of environmental temperatures on mammalian energetics and survival assume a constant body temperature. However, despite generally being regarded as strict homeotherms, mammals demonstrate a large degree of daily variability in body temperature, as well as the ability to reduce metabolic costs either by entering torpor, or by increasing body temperatures at high ambient temperatures. Often, changes in body temperature variability are unpredictable, and happen in response to immediate changes in resource abundance or temperature. In this review we provide an overview of variability and unpredictability found in body temperatures of extant mammals, identify potential blind spots in the current literature, and discuss options for incorporating variability into predictive mechanistic models

Avaliação da estimulação sensório-motora-oral na transição da alimentação enteral para a via oral plena em recém-nascidos pré-termo Evaluation of sensory-motor-oral stimulation in the transition from gastric tube to full oral feeding in preterm newborns

OBJETIVOS: avaliar a influência da estimulação sensório-motora-oral (SMO) sobre o ganho de peso, tempo para realizar a transição da sonda para a via oral e, indiretamente, sobre a alta hospitalar de pré-termos. MÉTODOS: estudo de intervenção, do tipo ensaio clínico controlado, que incluiu 24 pré-termos, internados na UTI Neonatal do Hospital Universitário de Santa Maria, Rio Grande do Sul, Brasil, entre maio de 2007 e março de 2008, alocados, por sorteio, em grupo estimulado (GE) e controle (GC). A análise das diferenças entre os grupos foi testada utilizando o teste t-Student independente e exato de Fisher (valor de p<0,05). RESULTADOS: não houve diferença estatística para as medidas antropométricas, embora o incremento diário de peso tenha sido maior no GE (p=0,16). O GE realizou a transição completa da sonda para a via oral em média 1,6 dias antes que o GC, sendo que 83,3% das crianças do GE fizeram essa transição em até sete dias, enquanto apenas 38,9% do GC alcançaram esse prazo. Não houve diferença no tempo de permanência hospitalar entre os grupos (p=0,48). CONCLUSÕES: a estimulação SMO favoreceu uma transição mais rápida da sonda para a via oral, não comprometendo o ganho de peso de recém-nascidos pré-termo. Não foi possível observar sua influência sobre o tempo de permanência hospitalar.<br>OBJECTIVES: to evaluate the influence of sensory-motor-oral (SMO) stimulation on weight gain, the time taken to make the transition from tube-to oral feeding and, indirectly, on the duration of hospitalization of preterm infants. METHODS: a controlled clinical intervention study was carried out with 24 preterm infants hospitalized in the Neonatal ICU of the Santa Maria University Hospital in the State of Rio Grande do Sul, Brazil, between May 2007 and March 2008, divided randomly into a treatment (TG) and control group (CG). The analysis of the differences between the groups was tested using Student&#39;s independent t-test and Fisher&#39;s exact test (with a p value <0.05). RESULTS: there was no statistical difference in terms of anthropometrical measurements, although the daily weight gain was higher in the TG (p=0.16). The TG group made a full transition from tube-to oral feeding on average 1.6 days earlier than the CG, 83.3% of the children in the TG making the transition within seven days, compared to only 38.9% of the control group. There was no difference in terms of the length of stay in hospital between the two groups (p=0.48). CONCLUSIONS: SMO stimulation was likely to lead to a swifter transition from tube-to oral feeding, without any adverse effect on weight gain in preterm newborns. No influence on the length of stay in hospital was observed